The purpose of this study is to evaluate the role of Antibody Dependent Cellular Cytotoxicity (ADCC) in inflammatory diseases of the skin. Epidermal cells in culture or suspension will be incubated with patients' sera and nonspecific mononuclear effectors to define if cell lysis is induced. The importance of this mechanism as a model of cutaneous inflammation will be studied using sera from patients with lichen planus, lupus erythematosus, erythema multiforme, alopecia, vitiligo, recurrent aphthous stomatitis and pyoderma gangrenosum. In addition, more accurate definition of the effectors of ADCC will be accomplished using counterflow centrifugation (elutriation) of effectors.